The purpose of this study is to examine the dose-response relationship of 6 different inhaled corticosteroids on adrenal gland suppression. Inhaled corticosteroids are anti-inflammatory drugs that are commonly used to treat asthma. These drugs affect the body's natural ability to produce cortisol, a hormone that is secreted by the adrenal gland. This studdy will determine which doses result in an equivalent degree of systemic (body) effect.